The present invention relates to an image processing apparatus and method for receiving compressed data and expanding the compressed data to develop image data.
An apparatus, which develops a rendering command (compressed data) input from a host computer or the like into bitmap data, determines attribute information corresponding to each pixel of the bitmap data using the input rendering command and its attribute information, and displays or prints an image obtained from the bitmap data, is known.
In such conventional apparatus, since sole attribute information is appended to the input compressed data, an attribute other than that attribute information cannot be designated for each pixel of image data after the compressed data has been expanded.
In recent years, a compression scheme that uses wavelet transformation has received a lot of attention.
The present invention has been made in consideration of the above prior art, and has as its object to provide an image processing apparatus and method, which receive as a rendering command obtained by compressing image data using wavelet transformation, and can efficiently process developed image data, when the rendering command is developed to image data and an image represented by the image data includes a plurality of attributes.
In order to attain the above described object, an image processing apparatus of the present invention comprises: input means for inputting compressed data, the compressed data including a data stream obtained by computing a wavelet transform of an image to obtain transform coefficients, shifting up bits of transform coefficients corresponding to a region of interest of the image, and entropy-encoding the shifted-up bits and bits of transform coefficients corresponding to a remaining region; generation means for generating first bitmap data by expanding the compressed data; interpretation means for interpreting the compressed data to discriminate a portion of the region of interest and a remaining portion in the first bitmap data; and conversion means for executing image processes of the portion of the region of interest and the remaining portion using different parameters on the basis of a discrimination result of the interpretation means to convert the portions into second bitmap data.
In order to attain the above described object, an image processing method of the present invention comprises the steps of: inputting compressed data, the compressed data including a data stream obtained by computing a wavelet transform of an image to obtain transform coefficients, shifting up bits of transform coefficients corresponding to a region of interest of the image, and entropy-encoding the shifted-up bits and bits of transform coefficients corresponding to a remaining region; generating first bitmap data by expanding the compressed data; interpreting the compressed data to discriminate a portion of the region of interest and a remaining portion in the first bitmap data; and executing image processes of the portion of the region of interest and the remaining portion using different parameters on the basis of a discrimination result in the interpreting step to convert the portions into second bitmap data.
Other features and advantages of the present invention will be apparent from the following descriptions taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.